Navigation system

ABSTRACT

A navigation system, which can determine a place suitable for meeting as a meeting place, is disclosed. This navigation system obtains positional information of mobile units, and extracts candidates for a meeting place from adequate meeting places registered in advance. The navigation system automatically selects or a user manually selects one place from the extracted candidates, and determines the selected one as the meeting place. The navigation system transmits the information about the meeting place to the other mobile units, so that the mobile units can meet each other at the right meeting place free from any place-caused inconvenience.

TECHNICAL FIELD

[0001] The present invention relates to a navigation system which canset a meeting place for a plurality of mobile units to meet each otherwith ease.

BACKGROUND ART

[0002] A navigation system, which sets a meeting place automatically andquickly, has been available for users who drive their cars to meet eachother by communicating with each other using in-car navigation devicesinstalled.

[0003] An instance of the foregoing navigation system is disclosed inJapanese Patent Application Non-Examined Publication No. 2000-88591.This system sets automatically a meeting place for the cars to meet eachother in the fastest way taking into account the information such as acruising speed of each car and traffic jam on the road.

[0004] In the foregoing conventional structure, the respectivenavigation devices, installed in the cars that want to meet each other,measure their own locations, and transmits those data to the masternavigation device. The master navigation device then extracts a meetingplace, where the cars can meet in the fastest way, taking into accountthe information such as cruising speeds of the respective cars andtraffic jam based on the location of the car having the masternavigation device and the locations of the other cars. The masternavigation device then transmits the meeting place extracted to all thenavigation devices installed in the other cars.

[0005] A conventional navigation system has a structure discussed above,so that the cars want to meet each other travel respectively to themeeting place transmitted from the master navigation device, and theycan meet each other in a fast manner.

[0006] However, the conventional navigation system simply extracts ameeting place to be reached fastest based on the locations of the carsthat want to meet each other, so that the meeting place extracted is notalways suitable for the cars to meet. For instance, extracting a roadhaving heavy traffic and difficult to park, a place with no parking lot,or a street jammed with cars as a meeting place is not always fit forcars to meet.

DISCLOSURE OF THE INVENTION

[0007] The present invention provides a navigation system that can set ameeting place suitable for cars to meet each other. The navigationsystem of the present invention comprises the following elements:

[0008] positional information obtaining means for obtaining positionalinformation of mobile units;

[0009] extracting means for extracting candidates for a meeting placebased on the obtained positional information from adequate meetingplaces registered in advance;

[0010] meeting place determining means for selecting one place as themeeting place from the extracted candidates for the meeting place; and

[0011] transmitting means for transmitting the selected meeting place tothe mobile units.

[0012] This structure allows selecting a meeting place from appropriatecandidates registered in advance for a meeting place, so that themeeting place cannot be an inconvenient location.

[0013] Another navigation system of the present invention comprises thefollowing elements:

[0014] positional information obtaining means for obtaining positionalinformation of its own mobile unit and other mobile units;

[0015] extracting means for extracting candidates for a meeting placebased on the obtained positional information from adequate meetingplaces registered in advance;

[0016] meeting place determining means for selecting one place as themeeting place from the extracted candidates for the meeting place; and

[0017] transmitting means for transmitting the selected meeting place tothe other mobile units.

[0018] This structure allows extracting plural meeting-place candidatessuitable for its own mobile unit and the other mobile units to meet,then selecting one place from the candidates, so that no inconvenientplace for the meeting place is selected. As a result, its own mobileunit and the other mobile units can meet each other at an appropriateplace.

[0019] The transmitting means of the present invention provides at leastone of map information to the meeting place, route guidance to themeeting place, an expected arrival time, and expected meeting time. Thisstructure allows the related mobile units to arrive exactly at theselected meeting place based on at least one of those information suchas map information to the meeting place, route guidance to the meetingplace, an expected arrival time, and expected meeting time.

[0020] The present invention extracts meeting-place candidates fromadequate meeting places which includes at least one of a station, busstop, supermarket, convenience store, park, public office, school,shopping mall, cinema complex, parking lot, open space, andintersection. This structure avoids determining an inconvenient place asa meeting place as the conventional system did, and determines asuitable place for cars to meet each other.

[0021] The navigation system of the present invention allows providingadequate meeting places with priorities respectively, and the meetingplace determining means selects one place according to the priorities.This structure allows determining a more suitable place for cars to meeteach other.

[0022] The navigation system of the present invention determines thepriorities taking into account the information including at leastavailability of a parking lot, an expected arrival time at themeeting-place candidates. This structure allows determining a prioritydepending on a combination of the mobile units to be met each other,e.g. a person and a person, a car and a car, or a person and a car. Tobe more specific, the system determines the priorities depending on theforegoing combination taking into account the information such as theavailability of a parking lot, and which party arrives earlier. As aresult, the system can select a meeting place without involving a personor a car into trouble.

[0023] The navigation system of the present invention further comprisesthe following elements:

[0024] display means for displaying the meeting-place candidatestogether with the priorities; and

[0025] operating means for manually selecting a meeting place.

[0026] This structure allows a user to select a preferable place byvisual confirmation instead of mechanical confirmation.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0027]FIG. 1 shows a schematic block diagram illustrating a navigationsystem in accordance with a first exemplary embodiment of the presentinvention.

[0028]FIG. 2 shows a flowchart illustrating an operation of thenavigation system shown in FIG. 1.

[0029]FIG. 3 shows a flowchart illustrating an operation of a navigationsystem in accordance with a second exemplary embodiment of the presentinvention.

[0030]FIG. 4 shows a flowchart illustrating an operation of a navigationsystem in accordance with a third exemplary embodiment of the presentinvention.

[0031]FIG. 5 shows a schematic drawing illustrating more specificallythe operations of the navigation systems in accordance with the first,second and third embodiments of the present invention.

[0032]FIG. 6 shows a schematic block diagram illustrating a navigationsystem of another exemplary embodiment of the present invention.

BEST MODE FOR PRACTICING THE INVENTION

[0033] Exemplary embodiments of the present invention are demonstratedhereinafter with reference to the accompanying drawings.

[0034] Exemplary Embodiment 1

[0035]FIG. 1 shows a schematic block diagram illustrating a navigationsystem in accordance with the first exemplary embodiment of the presentinvention. In FIG. 1, position sensor 11 includes a GPS receiver and aself-contained navigation measuring device, and senses a presentself-position before supplying it to navigation controller 12.

[0036] Memory 13 is formed of a CD-ROM or a DVD-ROM for storing mapinformation and candidates for a meeting-place. The map information andthe candidates stored in memory 13 are read out when necessary, andsupplied to navigation controller 12 following the control of controller12.

[0037] Operating section 14 is used for inputting information such as adestination, transit place, and a variety of instructions. Both of theinformation and the instructions input through operating section 14 aresupplied to navigation controller 12.

[0038] Transceiver 15 obtains service information of trains and buses,information of traffic jam on roads (including information of jam causedby railway crossings), information of road works, other traffic relatedinformation, and jam information at stations, bus stops, and parkinglots registered in advance. The foregoing information can be obtainedvia radio communication between transceiver 15 and a center device (notshown).

[0039] The information obtained by transceiver 15 is supplied tonavigation controller 12. Transceiver 15 can communicate with othernavigation devices via a direct radio communication or the public radiocommunications.

[0040] Navigation controller 12 reads the map information around thepresent location sensed by position sensor 11 from memory 13, anddisplays the map of the present location and its vicinity on display 16.If a destination or a transit place is input through operating section14, controller 12 also sets automatically the routes to the transitplace and the destination before displaying them on display 16.

[0041] When a given instruction is input through operating section 14,navigation controller 12 controls transceiver 15 based on theinstruction. Controller 12 obtains service information of trains andbuses, information of traffic jam on roads, information of road works,other traffic related information, and jam information at the spotsregistered in advance such as parking lots. The foregoing informationcan be obtained via radio communication between transceiver 15 and acenter device (not shown).

[0042] Navigation controller 12 obtains positional information of theother navigation devices, namely, the positional information of theother parties, via radio communications between transceiver 15 and theother navigation devices. Based on the positional information of theother parties and the service information as well as the jam informationpreviously obtained, navigation controller 12 extracts plural candidatesfor a place, e.g. several places, suitable for itself and the others tomeet each other from a large number of adequate meeting placesregistered in advance in memory 13. Then controller 12 displays them asthe plural candidates for a meeting place on display 16.

[0043] One place is selected from the plural candidates shown on display16 through operating section 14 for determining the one as the meetingplace. Navigation controller 12 transmits the following information tothe other parties: the meeting place determined, the map information androute guidance to the meeting place, and the meeting time and anexpected arrival time at the meeting place.

[0044] An operation of the navigation system discussed above isdemonstrated hereinafter with reference to FIG. 2 and FIG. 5.

[0045]FIG. 2 shows a flowchart illustrating an operation of thenavigation system in accordance with the first embodiment. FIG. 5 showsa schematic drawing illustrating more specifically the operation inaccordance with the first embodiment.

[0046] When some one wants to meet others, the one specifies desirableothers to meet by a key-operation using the one's own navigation device.Navigation controller 12 detects the key-operation, then instructstransceiver 15 to start radio-communication between the desirable othersand the one itself. Based on this radio-communication, navigationcontroller 12 assigns some navigation device to be a master navigationdevice and the others to be slave navigation devices.

[0047] The master device and the slave devices can be determined throughcommunications between the master device and the slave devices; however,any one of the devices can be assigned to be a master and the others canbe assigned to be slaves. For instance, a navigation device of a callingparty, a navigation device installed in a car, or a navigation device ofwhich navigation controller 12 has a higher processing capacity can beautomatically the master device. On the other hand, navigation devicesof called parties, portable navigation devices, or navigation devices ofwhich navigation controller 12 is a lower processing capacity can beautomatically slave navigation devices.

[0048] The assignment of the master navigation device prompts the masterdevice to communicate with the slave devices and the center device, andoperates as shown in FIG. 2.

[0049] For making the descriptions simpler, the master navigation deviceis referred to simply as “itself” and the slave navigation devices arereferred to simply as “others” hereinafter.

[0050] First, a navigation device is determined to be a master (S201),then the master navigation device requests other navigation devices,which are assigned to be slave devices, to transmit respective presentlocations to itself (S202).

[0051] When other navigation devices transmit their present locations toitself in response to the request, itself receives information of theothers locations (S203) and supplies the information to navigationcontroller 12.

[0052] Controller 12 calculates a tentative meeting place (S204) in aminimum time based on the information of other's locations and thepresent location of itself. Then controller 12 extracts pluralcandidates, e.g. several candidates for a meeting place, in the vicinityof the tentative meeting place from a large number of adequate meetingplaces stored in memory 13 in advance (S205).

[0053] In other words, a large number of places suitable for meetingplaces such as a station, bus stop, supermarket, convenience store,park, public office, community center, school, shopping mall, cinemacomplex, and open space, are stored in memory 13.

[0054] Navigation controller 12 extracts plural candidates, e.g. severalcandidates for a meeting place, from the large number of adequatemeeting places stored in memory 13.

[0055] Priorities are assigned to adequate meeting places stored inmemory 13 from the viewpoint of suitable for persons and cars to meeteach other. Navigation controller 12 extracts the plural candidates frommemory 13 (S205), then reads the priorities from memory 13, and displaysthem together with the candidates on display 16 (S206).

[0056] Use of the displayed priorities allows the user to select onemeeting place out of the plural candidates extracted, so that the userselects the one from the candidates through operating section 14 basedon the priorities displayed (S207) for determining the one as themeeting place.

[0057] Determination of the meeting place prompts controller 12 to setthe route to the meeting place and display it on display 16. Controller12 also transmits the selected meeting place and the route to themeeting place to the others via transceiver 15 (S208).

[0058] The others and itself thus follow the route guidance transmittedor the route guidance to the meeting place determined, and move towardthe meeting place, then they can meet each other efficiently at themeeting place. The meeting place in this case is selected from a numberof candidates suitable for persons and cars to meet, so that the placeshould not be an inconvenient place for the meeting. As a result, thenavigation system advantageously causes little trouble to the relatedpersons and cars.

[0059] In this embodiment, when one place is selected from pluralcandidates extracted (S207), a selection is done manually usingoperating section 14; however, the one place can be selectedautomatically by controller 12 based on the respective priorities. Inthis case, the following structure can also produce a similar advantageto what is discussed above: Step 206 of displaying the plural candidatestogether with the priorities can be omitted, and in step 207, only onemeeting place having the highest priority is selected without displayingthe plural candidates. In step 208, the selected meeting place isdisplayed together with the route guidance on display 16.

[0060] Next, a specific instance of the priorities of meeting places forpersons and cars to meet is described hereinafter.

[0061] The adequate meeting places for persons and cars are registeredin advance, they are a station, bus stop, supermarket, conveniencestore, park, public office, community center, school, shopping mall,cinema complex, and open space. In the case of assigning priorities tothose places, first of all, availability of a place for parking cars isconsidered, then the following conditions are set: if the parking placeis available, cars should arrive earlier than persons, and if not,persons should arrive earlier than cars. The priorities are thendetermined.

[0062] If the parking place is available, and yet, in the case of a payparking lot, it is not preferable to wait for a long time at the parkinglot, so that the priority of the meeting place is lowered if the fee isexpensive, and the priority is raised if the fee is inexpensive.

[0063] Further, if the meeting place is near to the tentative meetingplace, the priority is raised, and if it is distant, the priority islowered. If the person to meet is expected to use a train or a bus, thefare of the train or bus and a time on foot are taken into account, andthe priority is raised as the fare becomes less expensive and a time onfoot becomes shorter. As such, the priorities are assigned to respectivecandidates for a meeting place.

[0064] In the case of meeting cars each other, it is not critical whichcar arrives earlier, so that a candidate with a parking lot gets ahigher priority, and yet, if it is a free parking lot, the candidategets still higher priority.

[0065] Next, the case where car 101 meets person 102 is described withreference to FIG. 5. In this case, since person 102 is near the stationand the bus stop, it is expected that person 102 takes a train or a busto meet car 101. When taking the train or bus, person 102 needs thetime-table and the table of fare of the trains or bus. Thus transceiver15 firstly obtains those materials from the center device (not shown).Car 101 needs the information about traffic jam and road works, so thattransceiver 15 obtains the information from the center device.

[0066] Based on the foregoing information about the train, bus, androads, navigation controller 12 calculates the place where car 101 andperson 102 can meet fastest, and determines the place as a tentativemeeting place.

[0067] Assume that the present time is 13:00, a meeting place for car101 and person 102 to meet fastest is calculated in the following threecases:

[0068] (1) person 102 moves to station 301 by train;

[0069] (2) person 102 moves to station 302 by train; and

[0070] (3) person 102 walks along road 204.

[0071] The calculations produce the following results:

[0072] (1) person 102 moves to station 301 by train;

[0073] Person 102 takes a train from station 303 and arrives at station301 at 13:30, then walks along road 201. Car 101 drives on road 201 andencounters traffic jam. As a result, car 101 and person 102 can meet atposition 901 at 13:48.

[0074] (2) person 102 moves to station 302 by train;

[0075] Person 102 takes a train from station 303 and arrives at station302 at 13:20, then walks along road 205. Car 101 takes road 204 thenroad 205, and encounters road works on road 205. As a result, car 101and person 102 can meet at position 902 at 13:35.

[0076] (3) person 102 walks along road 204 and car 101 drives on road204:

[0077] Road 204 has no traffic jam, so that car 101 and person 102 canmeet at position 903 at 13:20.

[0078] Among the foregoing three cases, position 903 allows car 101 andperson 102 to meet each other fastest, so that navigation controller 102calculates position 903 as a tentative meeting place (S204).

[0079] In step 204, the tentative meeting place is calculated based on acondition that they can meet each other fastest; however, the presentinvention is not limited to this condition. Besides the time needed formeeting, a fare of train, bus, or taxi, and a toll of highway are takeninto account for calculating a tentative meeting place if the twoparties use such transportation. A walking speed of person 102 can beregistered in advance, or the speed can be set individually.

[0080] After the calculation of the tentative meeting place (S204) asdiscussed above, plural candidates for the meeting place are extractedfrom the adequate meeting places registered in advance (S205). Assumethat the tentative meeting place is position 903, then convenience store601 and parking lot 503 are extracted for example. Priorities areassigned to convenience store 601 and parking lot 503 based on theconditions proper to those places, and expected arrival times at thoseplaces. The conditions proper to those places include, e.g. availabilityof a parking lot, fee of the parking lot, and spaces available in theparking lot. The conditions proper to person 102 includes, e.g. whetheror not it takes over 30 minutes (registered as a limit time on foot) onfoot.

[0081] The priorities are calculated based on the conditions proper tothe candidates and expected arrival times at the respective candidates,then assigned to the candidates.

[0082] Assume that convenience store 601 and parking lot 503 have thefollowing conditions and expected arrival times:

[0083] (1) convenience store 601: parking lot: available and free ofcharge

[0084] expected arrival time of car 101: 13:22

[0085] expected arrival time of person 102: 13:15

[0086] (2) paring lot 503: parking lot: available with fee 200 yen every30 minutes

[0087] expected arrival time of car 101: 13:25

[0088] expected arrival time of person 102: 13:10

[0089] In the foregoing instance, convenience store 601 and parking lot503 have parking lots. Thus if car 101 arrives earlier than person 102,car 101 can wait in the parking lot, so that person 102 does notnecessarily arrive earlier than car 101. Based on this situation, theexpected arrival times and the fee of the parking lot, the prioritiesare determined as follows:

[0090] In the case of meeting at convenience store 601, person 102 walkslonger time than meeting at parking lot 503; however the time on foot(15 minutes) does not exceed the limit (e.g. 30 minutes but changeableby setting) for a human being to walk. Therefore, a higher priority isassigned to convenience store 601 than parking lot 503 because of thefree parking lot and the earlier meeting time. Then convenience store601 is selected (S207).

[0091] If the candidates for the meeting place include no parking lot,car 101 can temporarily stop at the roadside in order to pick up person102; however, car 101 must leave the roadside as soon as possible. Inthis case, person 102 is required to arrive at this meeting placeearlier than car 101. Thus a candidate, where person 102 might arrivelater than car 101, gets a lower priority than other candidates. Becauseif car 101 arrives earlier than person 102, car 101 possibly gets aticket due to parking violation, this possible situation is taken intoaccount for determining the priorities.

[0092] In the case of selecting one place according to the priorities,the selection can be done automatically; however, it can be manuallydone using the following method: Display the candidates, conditionsproper to the candidates, and expected arrival times of car and personon display 16, then select one place manually.

[0093] After the selection of convenience store 601, the map informationand route guidance to convenience store 601 together with the name ofconvenience store 601 are transmitted to the other party (S208).Following the map information and route guidance, car 101 and person 102move to convenience store 601, then person 102 arrives there at approx.13:15, and car 101 arrives at approx. 13:22. As a result, car 101 andperson 102 can meet each other at convenience store 601 at 13:22.

[0094] Next, the case, where car 101, person 102 and person 103 meeteach other, is described hereinafter with reference to FIG. 5. In thiscase a tentative meeting place for car 101, person 102 and person 103 iscalculated in step 204. Since persons 102 and 103 can take a train and abus respectively, transceiver 105 obtains the service and fareinformation of the train and the bus from the center device. Based onthe information from the center device and the information about trafficjam, road works and other traffic related information obtained bytransceiver 15, navigation controller 12 calculates a tentative meetingplace for car 101, person 102 and person 103.

[0095] Assume that the tentative meeting place is figured out as a placenear station 301, then plural candidates registered in advance andlocated in the vicinity of the tentative meeting place are extracted(S205), i.e. they are station 301, convenience store 602, parking lots501 and 502.

[0096] Priorities are assigned to those candidates extracted. Thefollowing factors are taken into account for determining the priorities;conditions proper to the candidates (availability of a parking lot,charge or free and fee of the parking lot), expected arrival time of car101, person 102 and person 103.

[0097] Those priorities are displayed together with the pluralcandidates on display 16 (S206), and one place with a higher priority isselected (S207). For instance, under the condition that the tentativemeeting place is close to station 301, if persons 102 and 103 can arriveat station 310 a little bit earlier than car 101, station A having thehighest priority is selected as the meeting place, then the mapinformation and route guidance to the selected meeting place aretransmitted together with the name of the meeting place to other parties(S208).

[0098] Car 101, person 102 and person 103 move to the selected meetingplace following the map information and route guidance, so that they canmeet each other at the meeting place with ease.

[0099] As discussed above, according to the first embodiment of thepresent invention, a tentative meeting place is firstly calculated basedon a present location of itself and those of the others. Then pluralcandidates, located in the vicinity of the tentative meeting place andregistered in advance, for a meeting place are extracted. Finally oneplace is selected as the meeting place based on the priorities assignedto the candidates.

[0100] The foregoing mechanism allows selecting a final one fromadequate meeting places registered in advance, so that the final onecannot be an inadequate place for meeting but can be always a favorableplace for meeting.

[0101] The candidates for the meeting place are assigned with prioritieswhich are determined in the following manner: a case where a person anda car meet each is taken into account, and if a parking lot isavailable, the car can arrive earlier than the person. If a parking lotis not available, the person must arrive earlier than the car. Thus itis advantageous that no parking violation or no trouble to the car andthe person occurs.

[0102] Exemplary Embodiment 2

[0103] The second embodiment is demonstrated with reference to FIG. 3,which shows a flowchart illustrating an operation of the navigationsystem in accordance with the second embodiment.

[0104] The second embodiment differs from the first one in the followingpoint: An input of a destination or a transit place on the way to thedestination through operating section 14 allows displaying the mapinformation and route guidance to the destination or the transit placeon display 16. The meeting place fastest to arrive is calculated takinginto account the destination or the transit place.

[0105] In FIG. 3, step 301-step 303 are similar to step 201-step 203shown in FIG. 2. Navigation controller 12 obtains present locations ofthe other parties that want to meet each other (S303). Then controller12 checks whether or not the destination (hereinafter including thetransit place) is already input (S304). If the destination is not yetinput, a fastest reachable meeting place is calculated based on its ownpositional information and those of the other parties as done in thefirst embodiment (S306). If the destination is already input, a fastestreachable meeting place is calculated based on the destination, its ownpositional information and those of the other parties (S305).

[0106] After the calculation of the fastest reachable meeting place(S305, S306), plural candidates for a meeting place are extracted fromadequate meeting places registered in advance (S307). The candidates arelocated in the vicinity of the fastest reachable meeting place. Then theplural candidates are displayed together with their priorities ondisplay 16 as done in the first embodiment (S308). One place is selectedmanually or automatically as the meeting place (S309), then the mapinformation and route guidance to the meeting place are transmittedtogether with the name of the meeting place to the other party (S310).

[0107] As discussed above, in this second embodiment, in the case ofinputting a destination, the fastest reachable meeting place isextracted, so that the most appropriate meeting place can be alwaysselected when the parties are on the way to the destination.

[0108] Next, a case where a destination is already input is detailedwith reference to FIG. 5. Assume that person 102 meets car 101 fordriving to a destination. In the first embodiment, car 101 and person102 simply want to meet each other as fast as possible, so that position903 is calculated as a tentative fastest reachable meeting place basedon the positional information of both the parties. However, in thesecond embodiment, an input of the destination is sensed by navigationcontroller 12 (S304), and controller 12 calculates a tentative meetingplace taking the destination into consideration (S305).

[0109] To be more specific, in the case of the second embodiment, when adestination is input at the navigation device of car 101, a routeguidance is produced such as “take road 201 via station 301 tointersection 403, then turn to left at intersection 403 and take road203 toward the destination”. A tentative meeting place for car 101 andperson 102 are calculated based on the foregoing route guidance. In thisinstance, even if it takes, more or less, a time to arrive at themeeting place, they can eventually arrive at the destination earlierthan the case when they meet at station 303. Therefore, e.g. a placenear station 301 is extracted as the tentative meeting place.

[0110] In the case of meeting persons 102, 103 and car 101 each otherbefore driving to a destination, a similar manner to what discussedabove is taken, for instance, a place in the vicinity of station 301 iscalculated as a tentative meeting place considering the route guidanceof car 101.

[0111] After that, in a similar manner to the first embodiment, pluralcandidates for a meeting place are extracted (S307), and displayed ondisplay 16 (S308). One place is selected from the displayed candidates(S309), then the map information, route guidance to the meeting placeare transmitted together with the name of the meeting place to each oneof the other parties (S310). The other parties and itself move to theselected meeting place following the map information and route guidance,thus they can meet each other at the selected meeting place with ease.

[0112] Exemplary Embodiment 3

[0113] The third exemplary embodiment is demonstrated hereinafter withreference to FIG. 4, which shows a flowchart illustrating an operationof the navigation system in accordance with the third embodiment of thepresent invention.

[0114] The third embodiment differs from the first and the second onesin adding steps 401-405 after step 207 and step 309 of the first and thesecond embodiments.

[0115] To be more specific, after the selection of one place from theplural candidates (S207, S309), the map information and route guidanceare transmitted together with the name of the selected one to each one.of the other parties (S401). If the selected one is unfavorable for oneof the other parties, the one of the other parties transmits a desirablemeeting place to the master itself (S402).

[0116] Based on a new meeting place transmitted from one of the otherparties, the master itself determines whether or not it is necessary tochange the meeting place (S403), and inputs the determination throughoperating section 14. If the change is necessary, itself changes themeeting place, and transmits the map information and route guidance tothe changed meeting place together with the name of the changed meetingplace to all the other parties (S404).

[0117] If the change is not needed, itself transmits a message of nochange only to the one who proposed the new meeting place (S405).

[0118] Here is a description about a specific instance with reference toFIG. 5. In FIG. 5, assume that persons 102, 103 and car 101 want to meeteach other before travelling to a destination. In this case, station 301is selected as a meeting place (S309), and this information istransmitted to persons 102 and 103 (S401).

[0119] Person 102 has no problem about the meeting place (station 301)selected; however, it is possible that person 103 has problem about thisplace. For instance, person 103 wants car 101 to take road 202 fromstation 301, and take road 203 via intersections 401 and 402 instead ofdriving via intersection 403. In another case, person 103 possibly wantsto take a bus and travel via intersection 401 toward intersection 402,and wants to meet the other parties at a place near intersection 402,but person 103 admits the driving route of car 101 to stay as it is.

[0120] In such a case, person 103 selects the nearest bus stop as adesirable meeting place and transmits it to the master navigation deviceif car 101 takes road 202 from station 301, then passes intersections401 and 402, then takes road 203. If person 103 wants to take bus andtravel via intersection 401 toward intersection 402, and wants to meetthe other parties at a place near intersection 402, person 103 specifiesone of convenient stores 603, 604, or parking lot 504, then transmitsthe specified one to the master (S402).

[0121] The master navigation device receives the information transmittedby person 103, then determines whether or not it is necessary to changethe meeting place (S403). If the change is necessary, the master changesthe meeting place, and transmits the map information and route guidanceto the changed meeting place together with the name of the changedmeeting place to not only person 103 who wants the change but alsoperson 102 (S404).

[0122] If the change is not needed, the master transmits a message of nochange only to person 103 (S405).

[0123] In the third embodiment, if the meeting place selected manuallyor automatically by the master is unfavorable for one of the slaves, theone slave transmits its desirable meeting place to the master, and achange of the meeting place depends on the master's choice. If themeeting place is changed, the change is noticed to all the slaves, sothat the master and the slaves can meet each other efficiently.

[0124] In the first, second and third embodiments, when a meeting placeis determined, a given operation through operating section 14 carriesout a sequence of actions. Thus if the meeting place is confirmedrepeatedly within the same parties, the same operation must be repeatedevery time. However, if the operation is once done, the operation can berepeated by returning automatically to step 202 or step 302 until theparties meet each other. For instance, the operation is repeated atintervals of 5 minutes, 10 minutes, or 15 minutes, or the intervals areshortened step by step such as, at a first interval in 10 minutes,second interval in 5 minutes and third interval in 2 minutes.

[0125] In the case of using the foregoing mechanism, as they areapproaching the meeting place, they can confirm their instant positions,thereby changing the meeting place manually or automatically in responseto the situation. As a result, they can determine an appropriate meetingplace more quickly, so that they can meet each other at the meetingplace more positively.

[0126] In embodiments 1-3, information obtained from the center deviceincludes time tables and fares of bus and train, other services, trafficjam, road works, other traffic news, and spaces available in a parkinglot. However, all the time-dependent information necessary for cars andpersons to meet each other can be obtained from the center device whichmanages or holds the foregoing information.

[0127] In embodiments 1-3, all the steps are executed by the masternavigation device, such as, determination of the master and the slaves(S201, S301), transmission of the map information and route guidance toa selected meeting place together with the name of the selected meetingplace to other parties (S208, S310). If the selected meeting place ischanged, the master device also execute the transmission of theinformation about the changed one to other parties (S404), if it is notchanged, transmission of a message of no change (S405). However, partsof those steps or all of those steps can be shared with the centerdevice or the slave navigation devices.

[0128] In short, the present invention is not limited to a stand-alonenavigation device installed in a vehicle or hand-carried, but comprisesthe system including a center device and navigation devices.

[0129] For instance, as shown in FIG. 6, navigation devices 61, 62, 63installed in a vehicle or hand-carried incorporate a memory of smallcapacity, and each of the devices is what is called a stand-alonenavigation device. When those devices want to set a meeting place, apartner to be met is designated, and the positional information of thepartner and itself is transmitted to center device 60, which thenexecutes the sequence of the foregoing actions, and transmits the nameof the meeting place and the route guidance to the meeting place tonavigation devices 61, 62 and 63 that want to meet each other. Theforegoing structure also produces the same advantage as what isdiscussed previously.

[0130] In this case, center device 60 can perform as follows before themeeting place is determined: Center device 60 firstly transmits pluralcandidates for a meeting place, conditions proper to the candidates, andexpected arrival times to the navigation device (e.g. device 61) thatwants to determine a meeting place. Navigation device 61 selects oneplace from the candidates, and transmits the selected one to centerdevice 60, which then transmits the route guidance and the name of theselected meeting place based on the selected one to the other navigationdevices, e.g. devices 62, 63.

[0131] Center device 60 can only extract the plural candidates, theconditions proper to the candidates, and expected arrival times, andother procedures can be executed by the master navigation device (e.g.device 61) and the slave navigation devices.

[0132] In short, as discussed previously, all of or parts of steps201-208 in embodiment 1, steps 301-310 in embodiment 2, and steps404-405 in embodiment 3 can be shared by center device 60 or slavenavigation devices 61, 62, and 63.

[0133] The foregoing structure allows a navigation system formed ofnavigation devices 61, 62, 63 to obtain map information and routeguidance from center device 60 respectively and to be capable of thisapplication. Each of the navigation devices has a memory of smallcapacity, and is what is called a communicating navigation device. Thisstructure allows center device 60 to provide services for meeting, sothat this system can invite people to join the system and provide themembers with the service for meeting each other free of charge or onchargeable basis.

[0134] Industrial Applicability

[0135] The navigation system of the present invention includespositional information obtaining means for obtaining positionalinformation of mobile units; extracting means for extracting candidatesfor a meeting place from adequate meeting places registered in advancebased on the positional information obtained; meeting place determiningmeans for selecting one place as the meeting place from the extractedcandidates for the meeting place; and transmitting means fortransmitting the meeting place to the mobile units. This structureallows selecting a meeting place from appropriate candidates registeredin advance for a meeting place, so that the navigation system issuitable for selecting a place favorable for meeting.

[0136] List of Reference Marks in Drawings

[0137]11 position sensor

[0138]12 navigation controller

[0139]13 memory

[0140]14 operating section

[0141]15 transceiver

[0142]16 display

[0143]60 center device

[0144]61, 62, 63 navigation device

[0145]101 car

[0146]102, 103 person

[0147]201, 202, 203, 204, 205 road

[0148]301, 302, 303 station

[0149]401, 402, 403 intersection

[0150]501, 502, 503, 504 parking lot

[0151]601, 602, 603, 604 convenience store

[0152]901, 902, 903 tentative meeting place

1. A navigation system comprising: positional information obtainingmeans for obtaining positional information of mobile units; extractingmeans for extracting candidates for a meeting place based on theobtained positional information from adequate meeting places registeredin advance; meeting place determining means for selecting one place asthe meeting place from the extracted candidates for the meeting place;and transmitting means for transmitting the selected meeting place tothe mobile units.
 2. The navigation system of claim 1, wherein thetransmitting means provides the mobile units with at least one of mapinformation to the meeting place, route guidance to the meeting place,an expected arrival time, and an expected meeting time.
 3. Thenavigation system of claim 1, wherein the adequate meeting placesinclude at least one of a station, bus-stop, supermarket, conveniencestore, park, public office, community center, school, shopping mall,cinema complex, parking lot, open space, and intersection.
 4. Thenavigation system of claim 1, wherein each one of the adequate meetingplaces is assigned with a priority as a meeting place, and the meetingplace determining means selects one place from the candidates accordingto the priorities.
 5. The navigation system of claim 4, wherein thepriority is determined by taking into account availability of a parkinglot and an expected arrival time at the candidates.
 6. The navigationsystem of claim 4 further comprising: display means for displaying thecandidates together with the priorities; and operating means forselecting manually the meeting place.
 7. A navigation system comprising:positional information obtaining means for obtaining positionalinformation of one mobile unit itself and other mobile units; extractingmeans for extracting candidates for a meeting place based on theobtained positional information from adequate meeting places registeredin advance; meeting place determining means for selecting one place asthe meeting place from the extracted candidates for the meeting place;and transmitting means for transmitting the selected meeting place tothe other mobile units.
 8. The navigation system of claim 7, wherein thetransmitting means provides the mobile units with at least one of mapinformation to the meeting place, route guidance to the meeting place,an expected arrival time, and an expected meeting time.
 9. Thenavigation system of claim 7, wherein the adequate meeting placesinclude at least one of a station, bus-stop, supermarket, conveniencestore, park, public office, community center, school, shopping mall,cinema complex, parking lot, open space, and intersection.
 10. Thenavigation system of claim 7, wherein each one of the adequate meetingplaces is assigned with a priority as a meeting place, and the meetingplace determining means selects one place from the candidates accordingto the priorities.
 11. The navigation system of claim 10, wherein thepriority is determined by taking into account availability of a parkinglot and an expected arrival time at the candidates.
 12. The navigationsystem of claim 10 further comprising: display means for displaying thecandidates together with the priorities; and operating means forselecting manually the meeting place.
 13. A navigation systemcomprising: a plurality of movable navigation devices; and a centerdevice that can communicate with the plurality of movable navigationdevices; wherein the movable navigation devices includes at least oneof: positional information obtaining means for obtaining positionalinformation of the navigation devices; extracting means for extractingcandidates for a meeting place based on the obtained positionalinformation from adequate meeting places registered in advance; meetingplace determining means for selecting one place as the meeting placefrom the extracted candidates for the meeting place; and transmittingmeans for transmitting the selected meeting place to the mobile unit,wherein the center device includes all the foregoing means except themeans that the navigation devices include.
 14. The navigation device asdefined in claim 13 including at least one of: positional informationobtaining means for obtaining positional information of one navigationdevice itself and other navigation devices; extracting means forextracting candidates for a meeting place based on the obtainedpositional information from adequate meeting places registered inadvance; meeting place determining means for selecting one place as themeeting place from the extracted candidates for the meeting place; andtransmitting means for transmitting the selected meeting place to thecenter device.